Apparatus for electro-anesthesia by means of contact electricity



July 15, 1958 KENSAKU SUZUKI 2,343,127

APPARATUS FOR ELECT ANESTHESIA BY MEANS CONTAC LECTRICITY F d NOV. 9, 1955 United States Patent APPARATUS FOR ELECTRO-ANESTHESIA BY MEANS OF CONTACT ELECTRICITY Kensaku Suzuki, Senju, Adachi-ku, Tokyo, Japan Application November 9, 1953, Serial No. 391,029

Claims priority, application Japan June 19, 1953 3 Claims. (Cl; 128303.1)

This invention relates to a non-stimulative operating apparatus in which the operating instrument such as a surgical knife or a dental bur, is connected with a metal different from the metal constituting said operating instrument, a carbon rod, or a carbon plate by means of a conducting wire, said diiferent metal or carbon rod or carbon plate being adapted to contact with a remote place of human body of a patient by being grasped, by the patients hand, of said metal or carbon body which is packed with cloths moistened with some electrolytic solution, such as physiological saline water. And therefore as soon as the operating instrument is made to contact with the human body, said .human body is transformed into a second conductor, an unipolar potential or a contact electricity being immediately developed at the contact point of the human body. Thereby a very weak direct electriccurrent is made to flow through an electric circuit constituted by the operating instrument, a lead wire, a diiferent metal or a carbon body, and the patients' human body. Generally speaking, when a very weak direct electric current is supplied upon the operating area during the surgical or dental operation, an alleviation of irritation is accomplished, so that by the above described electric current generated by means of the apparatusaccording to this invention, the mechanical, chemical and thermal irritations are entirely avoided during the operation, and pain and harmful elfects during said operation are extremely minimized.

In the accompanying drawing, Fig.1 shows a schematic drawing of an embodiment of this invention, Fig. 2 is a drawing representing some of the constituent parts of this invention, and Fig. 3 shows a modification of this invention.

In Fig. 1 illustrating an embodiment of this invention in a simplified form, 1 is an operating device such as a surgical knife, for example, 2 is a lead wire connected to a metal clip 1 provided at the upper end of said surgical knife, 3 is a carbon rod or the dilferent metal whose one extremity is earthed, 4 is a variable resistor controlling a very weak electric current, 6 is a microam meter, 7 is a condenser which should be used when it is necessitated as described hereinafter and should be inserted parallel between the grounded end and the metal clip 1' by means of a lead wire 8.

Because the operating instrument, such as a surgical knife, is generally made of steel, in order to generate sufficient contact electricity Within a human body, it is more desirable to use the metals having a higher unipolar potential as the different metal which is to be connected to a remote point of a human body, and the examples of such dilferent metal having a higher unipolar potential may be carbon, copper, or silver which has a higher unipolar potential than iron.

In considering an operating instrument in a human body, it is obvious that the surface portion of said instrument is dissolved electrochemically in the human body, so that the positive ions of iron are developed and electrons are made remain in the body of said instrument. Those electrons are transported within the lead wire to the another extremity of the device which is also made to contact with the remote portion of said human body. Therefore, an electric current is made to flow from the carbon rod to the operating instrument through the lead wire. Moreover, positive ions are continuously drawn from the surface of the instrument into human body, and this fact makes the potential of the operating area higher and higher than other portions of human body. The positive ions move from the operating area to the different metal or carbon rod through the human body.

It has previously been known that the excitability of nerve is decreased when the potential of the operating area becomes higher. When the operating instrument is connected to the diiferent metal and said metal is also connected to a human body, said different metal, the human body, and said instrument constitute an electric cell effectively. When the instrument is made as the negative pole of this cell, an equal result for operation can be obtained as in the case when said instrument is connected to a positive pole of an electric battery as was used usually.

Such being the case, none of usual electric source is necessitated in this invention. Because the potential difference which is to be impressed upon a human body by this instrument is very weak, there is no danger at all. For instance, when the carbon rod packed by cloth moistened by some physiological saline solution is connected to the body and this apparatus is connected to the instrument by a lead wire, the potential difference between the carbon rod and the instrument is about 0.35 volt and the current strength is about a few microamperes.

The potential difference between the instrument and the human body is determined by the potential relation between the different metal and the instrument, and therefore the leakage from the lead wire can be neglected. Consequently, the insulation between the instrument and the operator which is heretofore been necessitated for the conventional operating device is not required. So that the construction and manipulation of operating instrument becomes extremely easy.

Moreover, when a variable resistor 4 is inserted between the instrument and the different metal in order to adjust the amount of the current passing through the lead wire, like the adjustment given by an usual inner resistance of an electric battery generally used so that the optimum value of the current flowing in it, as shown in Fig. 1 (for example, when the current density at an unit area of operating instrument contacting with a human body is determined), an adjustment of the current according to the size of the operating instrument or the condition of contact of said instrument with the human body is not necessitated, and the manipulation of said instrument also becomes so simple.

As is also shown in Fig. 1, one end of said lead wire can be grounded and a condenser 7 can be inserted in it in order to so avoid the induction interference due to outside alternating current or sudden surge current which might be expected, that the potential of the operating part can be maintained at a constant value. But said induction interference due to an alternating current may be avoided when an end only is grounded, without the provision of a condenser 7.

Fig. 2 shows the carbon rod or difierent metal which should be connected to a remote part of the human body. Caps made of some suitable metal are mounted upon both terminals of carbon rod 3 by suitable means, and one of them is connected to the lead wire 2 and the other is grounded and connected to a lead wire 8 extending to one terminal of condenser 7. The main body of carbon rod 3 is packed by a cloth 9 moistened by electrolytic solution, such as the physiological saline solution. A carbon plate can be used in place of said carbon rod, and the foot of a patient may be connected to this plate, or this plate can be made to contact with a suitable part of the patient by knotting it by a rubber tape. The contact parts between the metal caps and the carbon rod or the different metal should be applied by Vaseline or silicone oil in order to prevent these parts getting wet by the electrolytic solution.

Fig. 3 shows a modification of this invention, in which the main body of the dififerent metal portion 3 is made as a hollow cylinder, and a condenser 7 and the variable resistor 4 is contained in it. The variable resistor 4 may be adjusted from outside of the body 3 by a suitable screw means.

Some practical examples of this invention may be described. A steel knife is used as the operating instrument, and a carbon rod is used as a different metal body, and a resistor having the value of to 50 kilo-ohms or 100 kilo-ohms is inserted as the variable resistance between both poles, said resistor being adjusted to control the strength of the electric current. The optimum strengths of the electric currents necessitated for electric anesthesia according to this invention are determined as follows by practical operations.

Elimination of pain in ivory portion of teeth (formation of a hole) Microamperes Front teeth 4 Small molar 4 Large molar 4-10 Elimination of pain at injection (hypodermic injection, painful Metaboline, l0 milligramme) Microamperes Steel injector (dia. 1/3 mm.) 12 Steel injector (dia. 1/5 mm.) l0

Scraping of teeth root -15 Operation of abscess 10 Above said resistor is adjusted to obtain the above described current values when the operating instrument is placed on a human body, and the operation is began.

Said operation provided the same result as the case when an usual operating device employing usual battery or an eliminator is used. But a stainless steel knife can not be used as it can not dissolved into a human body r source of power connecting said instrument and electrode with one another, said electrode being adapted to contact a part of the body remote from the operating area whereby a potential difference and resulting current are produced when said instrument is in contact with said operating area, and a variable resistor in said lead between said instrument and electrode to control said current and adjust it to a value below a critical value.

2. An apparatus for electro-anesthesia by means of contact electricity, comprising a metal operating instrument, an electrode formed of a conductive material different from that of said instrument, a lead wire connecting said instrument and electrode with one another, a cloth moistened with an electrolytic solution such as physiological saline water at least partially covering said electrode, the cloth being adapted to contact a part of the body remote from the operating area whereby a potential diflerence and resulting current are produced by electrolytic action when said instrument is in contact with said operating area, and a variable resistor in said lead between said instrument and electrode to control said current and adjust it to a value below a critical value, a terminal of said electrode being grounded and a condenser connected between the grounded terminal and the operating instrument in parallel with said resistor.

3. An apparatus for electro-anesthesia by means of contact electricity, comprising a metal operating instrument, an electrode formed of a conductive material different from that of said instrument, a lead wire connecting said instrument and electrode with one another, a cloth moistened with an electrolytic solution such as physiological saline water at least partially covering said electrode, the cloth being adapted to contact a part of the body remote from the operating area whereby a potential difference and resulting current are produced by electrolytic action when said instrument is in contact with said operating area, and a variable resistor in said lead between said instrument and electrode to control said current and adjust it to a value below a critical value, said electrode being constructed as a hollow cylinder, a condenser and said variable resistor being contained within said cylinder and said condenser being connected in parallel with said resistor.

References Cited in the file of this patent UNITED STATES PATENTS 566,103 Waite Aug. 18, 1896 2,069,112 Oppenheim Jan. 26, 1937 FOREIGN PATENTS 759,741 France Nov. 23, 1933 991,367 France June 20, 1951 OTHER REFERENCES Primary Batteries, a book by F. Cooper, published by Dean Bros., London, England, in 1920, p. 19. (Copy in Div. 60.) 

